Usando dois Past Perfects na mesma sentença

Hey everybody!

I came across this sentence the other day and found it soooooooo weird!

In: "Tell us something you had done but you wish you hadn't"

How come past perfect was used in the first part of the sentence as it is a fact however it doesn't show another sentence in the past to be preceded?

Is it ok or should it be simple past/present perfect and then a wish clause?

Thanks in advance,

Julia